Safety door latch

ABSTRACT

A novel door latch is provided in which a catch element is secured to the inside of a door lintel and a pivotal latch finger engages and is disengaged from the catch by the operating arm which opens and closes the door.

United States Patent [151 3,704,548

Wiegleb [451 Dec. 5, 1972 [54] SAFETY DOOR LATCH [56] References Cited [72] Inventor: Edward A. Wiegleb, Totowa, NJ. UNITED STATES PATENTS [73] Assignee: The Celotex Corporation, Tampa, 3,226,144 12/1965 Lomaz ..49/197 X Fla. 2,751,220 6/1956 Richmond ..49/200 [22] Filed: April 26, 1971 3,526,994 9/1970 Delaney "49/199 [21] Appl. No.: 137,510 Primary Examiner-Kenneth Downey Attorney-James W. Grace [52] US. Cl ..49/199 RA [51] int. Cl. .1205: 15/00 [57] ABST CT 53 Fidd f Search ag 197 199, 200 203 204, A novel door latch is provided in which a catch element is secured to the inside of a door lime] and a pivotal latch finger engages and is disengaged from the catch by the operating arm which opens and closes the door.

4 Claims, 5 Drawing Figures SAFETY DOOR LATCH BACKGROUND OFTHE INVENTION 1. Field of the Invention This invention is used most commonly with. garage doors on the one-piece vertically rising-horizontally stored type which are opened and closed by an operating arm.

2. Description of the Prior Art In the past most garage doors of the one-piece vertically opening-horizontally storing type were opened and closed by an operating arm which moved on a horizontal track supported below the garage ceiling. In most cases, it was felt that the armwhich usually was connected to a chain of a chain and sprocket drive would keep the door from unauthorized opening from outside the garage. It was found, however, that if the door were grasped along its lower edge and rocked back and forth, the operating arm could be moved back and the door opened from the outside without the operating mechanism of'the arm being energized.

Later, to prevent such unauthorized opening of the garage door, latch fingers were provided. These latch fingers were operated by the-control arm and engaged a catch which was fixed to the overhead track. In this way an attempt was made to prevent unauthorized opening of the door.

The mounting of the catch on the track requires a track which in some instances is undesirable. The track adds to the cost of the installation and entails extra labor expense. 2

In certain of the prior art latch devices the latch is spring biased so that a cam surface on the leading edge of the latch finger is used to liftthe latch finger before it engages a catch. Each time the latch finger operates, there is a certain amount of wear on the cam surface which. is undesirable. Furthermore, provision must be made to adjust the spring tension for the operation of the latch finger upon retraction of the operating member. The additional threaded members and adjusting nuts constitute an unneeded expense.

Furthermore, with a timed oscillatory movement of the door, the latch mechanism can be disengaged and the door opened by an unauthorized person.

SUMMARY OF THE INVENTION The present invention is directed to a safety door latch in which a catch is fixed to the interior portion of the door lintel independently of any track and the latch finger is moved upwardly to engage the catch by the positive action of the operating arm in closing the door. In operation, the latch finger more firmly grasps the catch if the door is subject to being opened from the outside.

It is an object of the present invention to provide a safety door latch which is easily installed and which requires a minimum of parts.

It is yet another object of the present invention to provide a novel safety door latch which prevents unauthorized opening of a vertically opening door from the outside.

Other objects and advantages of the present invention will become apparent to those skilled in the art when the following description is considered in conjunction with the accompanying drawing in which like numerals indicate like elements and in which:

FIG. 1 is a side elevational view of the novel door latch of the invention in its overall environment;

FIG. 2 is a top view of a portion of FIG. 1 showing the novel door latch of the present invention in greater detail showing the door latch in its latched condition;

FIG. 3 is a side view of the novel door latch illustrated in FIG. 2,

FIG. 4 is a partially cut-away view of the novel door latch taken along lines 4-4 of FIG. 2; and

FIG. 5 is a side elevational view of a portion of FIG. 1 in-greater detail, showing the doorlatch in its unlatched condition; y

Referring now to the drawing and particularly to FIG. 1 thereof, there is illustrated a building structure, preferably a garage having a floor slab l 1, an overhead or roof 12 and opening 14; the latter being adapted to be closed byan upwardly opening-downwardly closing door 16. A lintel 17 is constructed above the door opening 14 to form a support for the garage over the opening and has a lower edge 20 to receive the upper edge 21 of the door in relatively weathertight condition.

Door 16 is shown in a position intermediate full open and full closed position. The door is mounted on the door jamb 22 by any suitable mechanism, one type of which is shown and referred to by the numeral 25. A bracket 28 is affixed to the door and to a modified parallelogram linkage 30 which in turn is fixed to the door jamb 22 and the lower portion of door 16. A spring 32 is connected between linkage 30 and the fixed door jamb 22 to provide a biasing force to aid in the opening of the door.

The mechanism thus described is conventional and may take other forms, as desired.

To control the opening and closing of door 16 a control mechanism 35 is mounted near the ceiling of the garage at a point remote from the door. A chain 40 is connected to a sprocket drive wheel4l mounted on mechanism 35 and over a pulley sheave 43 which is supported on the inside of lintel 17 by a support member 44. Control mechanism 35 contains an electric motor which may be energized by an electric switch or by a remote control transmitter and receiver device. The operation ofcontrol mechanism to rotate sprocket wheel 41 in either a clockwise direction or a counterclockwise direction is conventional and well known to those skilled in the art.

To connect the door 16 to the chain drive 40, a control arm 48 is connected to a chain clamp device 50 and to a slotted plate assembly 52 secured to the inner top portion 20 of door 16 by bolts or screws 55.

Control arm 48 comprises an arm section 58 which may have a 90 offset so that control arm can move forward and rearward in a vertical plane in opening and closing the door 16. One end 59 of arm 48 is connected to chain clamp device by a pivotal connection 62. An extension 63 of arm 48 is connected to latch mechanism 52.

A catch 65 is mounted on lintel 17 by screws 68. Catch 65 may be a piece of metal bent at 90 so that one end may be secured to the lintel 17 while the other end 72 extends horizontally away from lintel 17 toward the interior of the garage. The height of catch 65 above the lower edge 20 of lintel 17 is adjusted to receive the finger end of a latch member 75, shown in greater detail in FIGS. 2 5. Catch 65 has an aperture 76 drilled or cut into its horizontal extending portion 72 to receive the finger of latch member 70 in a locking relationship.

Referring now to FIGS. 2 4,.slotted plate assembly 52 which connects control arm 48 to the top of door 16 and serves as a pivot connector for latch'member 75 comprises a pair of spaced plates 80 and 81 which are welded or otherwise integrally mounted on an angle iron 83. Angle iron 83 is secured to the top of door 16 by screws 55. Plates 80 and 81 are spaced slightly greater than the thickness of latch member 75 and control arm 48.

A pair of aligned slots 90 and 91 receive a bolt 93 which extends outwardly of the slots and is inserted for pivotal action through a hole near the end of control arm 48. A nut 97 is threaded on the end of bolt 93. A pair of tabs 100 and 101 are struck outwardly from each of plates 80 and 81respectively'. A pair of coil springs 105 and 106 are connected on each side respectively of plates 80 and 81 and connect bolt 93 to the tabs 100 and 101. As can be appreciated, the end 110 of arm 48 is movable between the spaced plates and is adjustable through a distance equal to the length of slots 90 and 91. The tension of springs 105 and 106 is maintained so that the advancing of control arm 48 by chain clamp 50 moves the upper end of door 16 into its closed position before the end 110 of control arm 48 moves forwardly against the spring tension. Thus, the tension of springs 105 and 106 is great enough to hold bolt 93 against the right hand ends of slots 90 and 91 (as seen in FIG. 5) until the closing motion of the door is stopped by the lintel 17. At that time the end 1100f control arm 48 is forced forward by the clockwise movement of chain 40 to overcome the tension. of springs 105 and 106 and moves to the left toward the left hand ends of slots 90 and 91. I

In opening the door, the control arm 48 is moved to the right and bolt 93 moves to the right hand ends of slots 90 and 91m relieve the tension of springs 105 and 106. It will, however, be recognized that in opening the door 16, there is a lost motion adjustment or time period between the initiation of movement of the control arm 48 to the right and the movement of the door 16 because the door 16 does not begin to open until the bolt 93 engages the right hand ends of slots 90 and 91. On the other hand, during closing, the door 16 strikes lintel 17 while the bolt 93 is still held against the right hand ends of slots 90 and 91. Further advancement of control arm 48 in a closing motion causes the end 110 to move toward lintel 17 against the tension of springs 105 and 106.

Latch member 75 is pivotally connected to plates 80 and 81 by a bolt 1 inserted through a hole in member 75. The hole is drilled in an ofiset manner so that when the latch member is free to move around the pivot provided by bolt 115 its leading edge 120 always falls downwardly under the influence of the force of gravity. The leading edge 120 is in the form of anupwardly extending finger 122 which engages slot 76 of catch 72 when the door 16 is closed and when control arm 48 is at its extreme advanced position. Finger 122 is disengaged from slot 76 of catch 72 when latch member 75 is free to pivot around pivot bolt 115.

The trailing (right hand) end of latch member has a downwardly bent portion 128 which has a cam surface 130. Cam surface 130 provides a riding surface fo the left end of control arm 48.

Keeping in mind the physical structure of the novel door latch, the operation will be described with reference to the closure and locking of the door from an open position and then the opening of the door from its locked position.

Referring to FIG. 5, it will be assumed that door 16 is to be closed and that control arm 48 is moved to the left by the clockwise movement of chain 40. At this time latch member 75 has its finger 122 in a downward position because. the leading end of control arm 48 is still held near the right hand end of slots and 91 under the biasing action of springs and 106. As the door 16 strikes portion 20 of lintel 17, the leading end of control arm 48 moves to the left in overcoming the tension of springs 105 and 106 and bolt 93 moves to the left in slots 90 and 91. The leading end 110 of control arm 48 rides against cam surface 130 of latch member 75 which then pivots about bolt to raise finger 122 into locking engagement. opening slot 76 in catch 72.-

Further movement of control arm 48 more firmly locks latch member 75 with catch 76 (as shown in FIGS. 3 and 4).

If someone attempts to" open the door from the outside by lifting the door at its bottom, he will only succeed in further increasing the locking action between the latch member 75 and the'catch 72. There is no component of movement in a horizontal direction to open the door.

In opening the door, control arm 48 is moved to the right by the movement of chain 40. The left hand end 110 of control arm 48 moves to the right and carries bolt 93 toward the right hand ends of slots 90 and 91. This movement relieves the tension of springs 105 and 106. As the left hand end 110 of control arm 48 clears cam surface of end 128 of latch member 75, the latter is freed from restraint and under the influence of gravity, pivots about bolt 115. Finger 122 falls out of engagement with catch-72 and the door is free to open as control arm 48 continues its movement to the right. There is ,a lost motion action between the initial movement of control arm 48 to the right and the movement of the door 16 while the bolt 93 moves from its left hand position to its right hand position in slots 90 and 91.

While the novel latch mechanism of the invention has been illustrated in conjunction with a solid onepiece garage door, sectional garage doors could easily be accomodated.

In summary, the present invention concerns a safety door latch for garage doors in which a latch member is positively locked in a catch which is securely mounted on the lintel above the door. The control arm which opens and closes the door also operates the engagement and disengagement of the latch member and the catch. I

I claim:

1. A door latch for locking an upwardly-opening,

I downwardly-closing door of which the upper, inner top area lies in close proximity to a horizontal lintel in its closed position comprising;

an apertured catch member mounted on said lintel,

said apertured catch member being adapted to receive in locking relationship an upwardly projecting finger of a pivoted latch member,

a pivoted latch member mounted on said upper, inner top area of said door for pivotal movement in a vertical plane,

said pivoted latch member having at one end an upwardly projecting finger which is movable between an engaged position and a disengaged position with respect to said catch member,

said pivoted latch member further comprising a unitary piece of metal pivotally mounted between two spaced metal plates, said plates being attached to the upper, inner top area of said door, said plates further having aligned slots for the reception of slideable connecting means for opening and closing said door and said latter means including a pin means received in said slots, and

means for opening and closing said door, including a resilient means which inhibits contact between said opening and closing means and said latch member before full closure of said door during the door closing function of said opening and closing means and permits said latch member to disengage from said catch immediately prior to the opening movement of said door.

2. A door latch as recited in claim 1 in which said pivoted latch member has a catch engaging finger and a cam surface, and has its pivot point intermediate said catch engaging finger and said cam surface, said pivot point being offset with respect to its center of gravity so that a preselected end thereof drops when said latch member is free from external forces.

3. A door latch as recited in claim 1 in which said resilient means comprises a pair of coil springs.

4. A door latch as recited in claim 2 in which said means for opening and closing said door has one end thereof adapted to contact and ride upon said cam surface of said latch member to cause said latch member of pivot and lift said catch engaging finger into locking engagement with said catch member. 

1. A door latch for locking an upwardly-opening, downwardlyclosing door of which the upper, inner top area lies in close proximity to a horizontal lintel in its closed position comprising; an apertured catch member mounted on said lintel, said apertured catch member being adapted to receive in locking relationship an upwardly projecting finger of a pivoted latch member, a pivoted latch member mounted on said upper, inner top area of said door for pivotal movement in a vertical plane, said pivoted latch member having at one end an upwardly projecting finger which is movable between an engaged position and a disengaged position with respect to said catch member, said pivoted latch member further comprising a unitary piece of metal pivotally mounted between two spaced metal plates, said plates being attached to the upper, inner top area of said door, said plates further having aligned slots for the reception of slideable connecting means for opening and closing said door and said latter means including a pin means received in said slots, and means for opening and closing said door, including a resilient means which inhibits contact between said opening and closing means and said latch member before full closure of said door during the door closing function of said opening and closing means and permits said latch member to disengage from said catch immediately prior to the opening movement of said door.
 2. A door latch as recited in claim 1 in which said pivoted latch member has a catch engaging finger and a cam surface, and has its pivot point intermediate said catch engaging finger and said cam surface, said pivot point being offset with respect to its center of gravity so that a preselected end thereof drops when said latch member is free from external forces.
 3. A door latch as recited in claim 1 in which said resilient means comprises a pair of coil springs.
 4. A door latch as recited in claim 2 in which said means for opening and closing said door has one end thereof adapted to contact and ride upon said cam surface of said latch member to cause said latch member of pivot and lift said catch engaging finger into locking engagement with said catch member. 